Customized patient-specific revision surgical instruments and method

ABSTRACT

A method of fabricating a customized patient-specific guide block is disclosed. The method includes generating a image of a patient&#39;s bony anatomy and an implanted prosthetic component secured to the patient&#39;s bony anatomy, identifying landmarks on the patient&#39;s bony anatomy and the prosthetic component, selecting a revision surgical instrument based the image and the landmarks, and manufacturing the customized patient-specific guide block including a customized prosthesis-specific negative contour shaped to match a corresponding contour of the implanted prosthetic component.

This application is a divisional of U.S. patent application Ser. No.14/848,795, now U.S. Pat. No. 9,398,919, filed Sep. 9, 2015, which is adivisional of U.S. patent application Ser. No. 13/793,407, now U.S. Pat.No. 9,131,945, filed Mar. 11, 2013, which is hereby incorporated byreference.

TECHNICAL FIELD

The present disclosure relates generally to customized orthopaedicsurgical instruments, and in particular to surgical instruments thathave been customized to interface with specific prostheses and patients.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a total knee arthroplasty surgical procedure, apatient's natural knee joint is partially or totally replaced by aprosthetic knee joint or knee prosthesis. A typical knee prosthesisincludes a tibial tray, a femoral component, and a polymer insert orbearing positioned between the tibial tray and the femoral component.The tibial tray generally includes a plate having a stem extendingdistally therefrom, and the femoral component generally includes a pairof spaced apart condylar elements, which include surfaces thatarticulate with corresponding surfaces of the polymer bearing. The stemof the tibial tray is configured to be implanted in asurgically-prepared medullary canal of the patient's tibia, and thefemoral component is configured to be coupled to a surgically-prepareddistal end of a patient's femur

From time-to-time, a revision knee surgery may need to be performed on apatient. In such a revision knee surgery, the previously-implanted kneeprosthesis, sometimes called a “primary knee prosthesis,” is surgicallyremoved and a replacement or revision knee prosthesis is implanted. Insome revision knee surgeries, all of the components of the primary kneeprosthesis, including, for example, the tibial tray, the femoralcomponent, and the polymer bearing, may be surgically removed andreplaced with revision prosthetic components. In other revision kneesurgeries, only part of the previously-implanted knee prosthesis may beremoved and replaced.

During a revision knee surgery, the orthopaedic surgeon typically uses avariety of different orthopaedic surgical instruments such as, forexample, cutting blocks, reamers, drill guides, prosthetic trials, andother surgical instruments to prepare the patient's bones to receive theknee prosthesis. Typically, the orthopaedic surgical instruments aregeneric with respect to the patient such that the same orthopaedicsurgical instrument may be used on a number of different patients duringsimilar orthopaedic surgical procedures.

SUMMARY

According to one aspect of the disclosure, a surgical instrumentincluding a customized patient-specific guide block is disclosed. Thecustomized patient-specific guide block includes a first surface, abone-facing surface, a second surface positioned opposite the firstsurface and the bone-facing surface, and a guide pin hole extendingbetween the second surface and the bone-facing surface. The firstsurface has a customized prosthesis-specific negative contour shaped tomatch a corresponding contour of a prosthetic component. The customizedprosthesis-specific negative contour includes a concave surface shapedto match a convex surface of the corresponding contour of the prostheticcomponent.

In some embodiments, the bone-facing surface may include a lateralsurface of the guide block, and the second surface may include a medialsurface of the guide block. In some embodiments, the prostheticcomponent may be a femoral prosthetic component. The convex surface ofthe corresponding contour of the femoral prosthetic component mayinclude a medial condyle surface, and the concave surface of thecustomized prosthesis-specific negative contour may include a medialconcave surface.

Additionally, in some embodiments, the bone-facing surface may include aposterior surface of the guide block, and the second surface may includean anterior surface of the guide block.

In some embodiments, the bone-facing surface of the guide block may havea customized patient-specific negative contour shaped to match acorresponding bone contour of a femur of a patient. The customizedpatient-specific negative contour may include a unique plurality ofdepressions and ridges that match a corresponding plurality of ridgesand depressions of the corresponding bone contour of the femur of thepatient.

In some embodiments, the guide block further may include asubstantially-planar cutting guide surface extending between thebone-facing surface and the second surface.

In some embodiments, the prosthetic component may be a tibial trayincluding a curved surface, and the convex surface of the correspondingcontour of the tibial tray may include the curved surface. The concavesurface of the customized prosthesis-specific negative contour mayinclude a curved inner surface.

According to another aspect, a method of performing an orthopaedicsurgical procedure is disclosed. The method includes aligning acustomized patient-specific guide block with a first prostheticcomponent implanted in an end of a bone of a patient, attaching thecustomized patient-specific guide block to the first prostheticcomponent in a unique location and orientation on the end of the bone,and advancing a guide pin through a guide pin hole of the customizedpatient-specific guide block into the bone when the customizedpatient-specific guide block is positioned on the first prostheticcomponent. The method also includes detaching the customizedpatient-specific guide block from the first prosthetic component and theend of the bone while leaving the guide pin secured to the bone,removing the first prosthetic component from the end of the bone,engaging an alignment block with the guide pin to position a cuttingblock on the bone, and resecting the end of the bone using the cuttingblock to guide the resection.

In some embodiments, positioning the customized patient-specific guideblock on the first prosthetic component in the unique location andorientation may include engaging a customized prosthesis-specificnegative contour of the customized patient-specific guide block with acorresponding contour of the first prosthetic component. The customizedprosthesis-specific negative contour may be shaped to match thecorresponding contour of the first prosthetic component.

In some embodiments, the first prosthetic component may include afemoral prosthetic component having a pair of curved condyle surfacesconfigured to engage a bearing surface. Additionally, engaging thecustomized prosthesis-specific negative contour of the customizedpatient-specific guide block with the corresponding contour of the firstprosthetic component may include engaging a concave surface of thecustomized patient-specific guide block with a medial condyle surface ofthe femoral prosthetic component.

In some embodiments, the method may include securing the alignment blockto the cutting block and engaging the alignment block with the guide pinmay include advancing the cutting block along an anatomical axis of thebone to advance the alignment block into contact with the guide pin. Insome embodiments, the alignment block may include an indicator of atarget joint line of a second prosthetic component.

In some embodiments, the method may include assembling the customizedpatient-specific guide block by locking a first removable drill bushinginto a first hole of a customized patient-specific pin guide, andlocking a second removable drill bushing into a second hole of thecustomized patient-specific pin guide. In some embodiments, the cuttingblock may include a patient-universal cutting block having a distalcutting guide.

In some embodiments, engaging the alignment block with the guide pin toposition the cutting block on the bone may include positioning the guidepin in a guide pin hole of the alignment block, advancing the alignmentblock into contact with the cutting block, engaging the cutting blockwith the bone, and aligning the cutting block with an indicator definedon the alignment block. The indicator may correspond to a targetanterior-posterior position of the cutting block.

In some embodiments, the method may include advancing a bone saw along acutting guide surface of the customized patient-specific guide blockwhen the customized patient-specific guide block is positioned on thefirst prosthetic component. In some embodiments, attaching thecustomized patient-specific guide block to the first prostheticcomponent may include engaging a customized patient-specific negativecontour shaped to match a corresponding contour of the bone of thepatient with the bone of the patient. The customized patient-specificnegative contour may include a unique plurality of depressions andridges that match a corresponding plurality of ridges and depressions ofthe corresponding contour of the bone of the patient.

According to another aspect, a method of fabricating a customizedpatient-specific guide block is disclosed. The method includesgenerating a image of a patient's bony anatomy and an implantedprosthetic component secured to the patient's bony anatomy, identifyinglandmarks on the patient's bony anatomy and the prosthetic component,selecting a revision surgical instrument based the image and thelandmarks, and manufacturing the customized patient-specific guide blockincluding a customized prosthesis-specific negative contour shaped tomatch a corresponding contour of the implanted prosthetic component. Thecustomized prosthesis-specific negative contour includes a concavesurface shaped to match a convex surface of the corresponding contour ofthe implanted prosthetic component.

In some embodiments, selecting the revision surgical instrument mayinclude generating a second image showing a planned position of therevision surgical instrument relative the patient's bony anatomy.

In some embodiments, the method may include manufacturing a secondcustomized patient-specific guide block based on the planned position ofthe revision surgical instrument. The second customized patient-specificguide block may include an indicator of the planned position.

In some embodiments, the method may include selecting a revisionorthopaedic prosthesis based the image and the landmarks. Additionally,selecting the revision orthopaedic prosthesis may include selecting afirst revision orthopaedic prosthesis from a plurality of revisionorthopaedic prostheses, overlaying a digital template of the firstrevision orthopaedic prosthesis on the image to create a second imageshowing the first revision orthopaedic prosthesis implanted in thepatient's bone, and selecting a second revision orthopaedic prosthesisfrom the plurality of revision orthopaedic prostheses based on thesecond image.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a simplified flow diagram of an algorithm for designing andfabricating a customized patient-specific orthopaedic surgicalinstrument;

FIG. 2 is a perspective view of a primary orthopaedic knee prosthesisimplanted in a patient's body;

FIG. 3 is a converted image of the primary orthopaedic knee prosthesisof FIG. 2;

FIG. 4 is a view similar to FIG. 3 showing a pre-operative assessment ofthe primary orthopaedic knee prosthesis;

FIG. 5 is another view of the primary orthopaedic knee prosthesis ofFIG. 2 and the pre-operative assessment;

FIG. 6 is an anterior view of a three-dimensional model of the patient'sbody including a digital template of a revision orthopaedic kneeprosthesis;

FIG. 7 is a medial view of the three-dimensional model of the patient'sbody including the digital template of the revision orthopaedic kneeprosthesis;

FIG. 8 is an exploded perspective view of a customized patient-specificfemoral pin guide and a pair of removable drill bushings;

FIG. 9 is a perspective view of the customized patient-specific femoralpin guide of FIG. 8 showing a negative contour;

FIG. 10 is a cross section view of the customized patient-specificfemoral pin guide and the removable drill bushings taken along the line10-10 of FIG. 8, as viewed in the direction of the arrows;

FIG. 11 is a perspective view of a customized patient-specific alignmentbracket and a distal cutting guide block;

FIG. 12 is a plan view of the customized patient-specific alignmentbracket of FIG. 11;

FIG. 13 is a side elevation view of the customized patient-specificalignment bracket of FIGS. 11-12;

FIG. 14 is an anterior elevation view of the customized patient-specificalignment bracket of FIGS. 11-13;

FIG. 15 is a perspective view of a customized patient-specific alignmentguide and a 4-in-1 cutting guide block;

FIG. 16 is an anterior elevation view of the customized patient-specificalignment guide of FIG. 15;

FIG. 17 is a perspective view of the primary femoral prostheticcomponent of FIG. 2 attached to a distal end of a patient's femur andthe customized patient-specific femoral pin guide of FIG. 8;

FIG. 18 is a medial perspective view of the primary femoral prostheticcomponent attached to a distal end of a patient's femur and thecustomized patient-specific femoral pin guide positioned thereon;

FIG. 19 is a lateral perspective view of the primary femoral prostheticcomponent attached to a distal end of a patient's femur and thecustomized patient-specific femoral pin guide positioned thereon;

FIG. 20 is a view similar to FIG. 18 showing a pair of guide pinsinstalled in the patient's femur;

FIG. 21 is a view similar to FIG. 20 showing the drill bushings removedfrom the customized patient-specific femoral pin guide;

FIG. 22 is a view similar to FIG. 21 showing the customizedpatient-specific femoral pin guide detached from the primary femoralprosthetic component and the patient's femur and the pair of guide pinsinstalled in the patient's femur;

FIG. 23 is a view similar to FIG. 22 showing the pair of custom-locatedguide pins installed in the patient's femur;

FIG. 24 is a medial perspective view of the patient's femur showing anintramedullary shaft inserted therein;

FIG. 25 is a view similar to FIG. 24 showing a femoral locating deviceattached to the intramedullary shaft of FIG. 24;

FIG. 26 is a view similar to FIG. 25 showing the distal cutting guideblock of FIG. 11 attached to the femoral locating device and thealignment bracket of FIGS. 11-14 aligned with one of the distal cuttingguides;

FIG. 27 is a view similar to FIG. 26 showing the alignment bracketsecured to the distal cutting guide block;

FIG. 28 is an anterior elevation view of the patient's femur showing thealignment bracket secured to the distal cutting guide block and engagedwith the custom-located guide pins;

FIG. 29 is a medial perspective view showing the 4-in-1 cutting guideblock of FIG. 15 engaged with the distal end of the patient's femur andthe intramedullary shaft;

FIG. 30 is a view similar to FIG. 29 showing the customizedpatient-specific alignment guide of FIGS. 15 and 16 engaged with the4-in-1 cutting guide block and the custom-located guide pins;

FIG. 31 is a distal elevation view of the patient's femur showing thealignment guide engaged with the 4-in-1 cutting guide block and thecustom-located guide pins;

FIG. 32 is a medial perspective view of the surgically-prepared distalend of the patient's femur;

FIG. 33 is a perspective view of another embodiment of a customizedpatient-specific femoral pin guide;

FIG. 34 is a posterior elevation view of the customized patient-specificfemoral pin guide of FIG. 33;

FIG. 35 is a medial side elevation view of the customizedpatient-specific femoral pin guide of FIGS. 33-34 attached to thepatient's femur;

FIG. 36 is a perspective view of another embodiment of a customizedpatient-specific femoral pin guide including a distal cutting guide;

FIG. 37 is an anterior elevation view of the femoral pin guide of FIG.36 attached to the patient's femur;

FIG. 38 is a perspective view of a customized patient-specific tibialpin guide and the primary tibial tray of FIG. 2 attached to thepatient's tibia;

FIG. 39 is a fragmentary cross sectional view of the customizedpatient-specific tibial pin guide of FIG. 38 taken along the line 39-39in FIG. 38, as viewed in the direction of the arrows;

FIG. 40 is a fragmentary elevation view of the customizedpatient-specific tibial pin guide of FIG. 38; and

FIG. 41 is an anterior elevation view of the customized patient-specifictibial pin guide of FIG. 38 attached to the primary tibial tray.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopaedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring to FIG. 1, an algorithm 10 for fabricating a customizedpatient-specific orthopaedic surgical instrument is illustrated. What ismeant herein by the term “customized patient-specific orthopaedicsurgical instrument” is a surgical tool for use by a surgeon inperforming an orthopaedic surgical procedure that is intended, andconfigured, for use on a particular patient. As such, it should beappreciated that, as used herein, the term “customized patient-specificorthopaedic surgical instrument” is distinct from standard, non-patientspecific orthopaedic surgical instruments (i.e., “patient-universalinstruments” such as patient-universal cutting blocks) that are intendedfor use on a variety of different patients and were not fabricated orcustomized to any particular patient. Additionally, it should beappreciated that, as used herein, the term “customized patient-specificorthopaedic surgical instrument” is distinct from orthopaedic prosthesesor implants, whether patient-specific or generic, which are surgicallyimplanted in the body of the patient. Rather, an orthopaedic surgeonuses customized patient-specific orthopaedic surgical instruments toassist in the implantation of orthopaedic prostheses. Examples of“customized patient-specific orthopaedic surgical instruments” includecustomized patient-specific drill/pin guides, customizedpatient-specific tibial cutting guide blocks, customizedpatient-specific femoral cutting guide blocks, and customizedpatient-specific alignment guides.

In some embodiments, the customized patient-specific orthopaedicsurgical instrument may be configured to interface with apatient-universal instrument to position the patient-universalinstrument in a preplanned location relative to the bone or bones of thepatient. The customized patient-specific orthopaedic surgical instrumentmay also be customized to the particular patient based on the locationat which the instrument is to be coupled to one or more bones of thepatient, such as the femur and/or tibia. For example, in someembodiments, the customized patient-specific orthopaedic surgicalinstrument may include a bone-contacting or facing surface having anegative contour that matches or substantially matches the contour of aportion of the relevant bone of the patient. As such, the customizedpatient-specific orthopaedic surgical instrument is configured to becoupled to the bone of a patient in a unique location and position withrespect to the patient's bone. That is, the negative contour of thebone-contacting surface is configured to receive the matching contoursurface of the portion of the patient's bone to position the customizedpatient-specific orthopaedic surgical instrument at the unique locationand position with respect to the patient's bone.

In revision surgical procedures in which the previously implanted orprimary prosthesis is surgically removed and a replacement prosthesis isimplanted, the customized patient-specific orthopaedic surgicalinstrument may be customized to engage the primary prosthesis before itis removed to position the instrument in a unique location and positionrelative to one or more bones of the patient. In such embodiments, thecustomized patient-specific orthopaedic surgical instrument may includea prosthesis-engaging or contacting surface having a negative contourthat matches or substantially matches the contour of a portion of theimplanted primary prosthesis. That is, the negative contour of theprosthesis-engaging surface is configured to receive the matchingcontour surface of the portion of the implanted primary prosthesis toposition the customized patient-specific orthopaedic surgical instrumentat a unique location and position with respect to the primary prosthesisand thus the patient's bone. Because the customized patient-specificorthopaedic surgical instrument is configured to be coupled to thepreviously implanted prosthesis and patient's bone in the uniquelocation and position, the orthopaedic surgeon's guesswork and/orintra-operative decision-making with respect to the placement of theorthopaedic surgical instrument are reduced.

For example, the orthopaedic surgeon may not be required to locatelandmarks of the patient's bone to facilitate the placement of theorthopaedic surgical instrument, which typically requires some amount ofestimation on part of the surgeon. Rather, the orthopaedic surgeon maysimply couple the customized patient-specific orthopaedic surgicalinstrument on the implanted primary prosthesis and bone or bones of thepatient in the unique location. When so coupled, the cutting plane,drilling/pinning holes, milling holes, and/or other guides are definedin the proper location relative to the bone and intended orthopaedicprosthesis. The customized patient-specific orthopaedic surgicalinstrument may be embodied as any type of orthopaedic surgicalinstrument such as, for example, a bone-cutting block, a drilling/pinguide, a milling guide, or other type of orthopaedic surgical instrumentconfigured to be coupled to a bone and/or the implanted primaryprosthesis of a patient.

It should also be appreciated that in some embodiments the customizedpatient-specific orthopaedic surgical instrument may include both aprosthesis-engaging or contacting surface having a negative contourmatching or substantially matching the contour of a portion of theimplanted primary prosthesis and a bone-contacting or facing surfacehaving a negative contour matching or substantially matching the contourof a portion of the relevant bone of the patient. In such embodiments,the negative contour of the prosthesis-engaging surface is configured toreceive the matching contour surface of the portion of the implantedprimary prosthesis and the negative contour of the bone-contactingsurface is configured to receive the matching contour surface of theportion of the patient's bone to position the customizedpatient-specific orthopaedic surgical instrument at a unique locationand position with respect to the implanted primary prosthesis and thepatient's bone.

In some embodiments, one or more customized patient-specific orthopaedicsurgical instruments may be customized to engage one or more prostheticcomponents of a primary knee prosthesis such as the primary kneeprosthesis 12 shown in FIG. 2. The primary knee prosthesis 12 includes aprimary femoral prosthetic component 14 secured to a distal end 16 of apatient's femur 18 and a primary tibial prosthetic component 20. In theillustrative embodiment, the primary tibial prosthetic component 20includes a tibial tray 22 secured to a proximal end 24 of a patient'stibia 26 and a tibial bearing 28 that is positioned between the tibialtray 22 and the primary femoral prosthetic component 14. The tibialbearing 28 includes a pair of curved concave bearing surfaces 30 thatengage a pair of corresponding curved convex condyle surfaces 32, 34 ofthe primary femoral prosthetic component 14. As described in greaterdetail below, a customized patient-specific orthopaedic surgicalinstrument may be configured to engage, for example, one or both of thecondyle surfaces 32, 34 of the primary femoral prosthetic component 14to position the customized patient-specific orthopaedic surgicalinstrument relative to the distal end 16 of the patient's femur 18.Another customized patient-specific orthopaedic surgical instrument maybe configured to engage part of the tibial tray 22 to position thepatient-specific orthopaedic surgical instrument relative to theproximal end 24 of the patient's tibia 26. In some embodiments, thecustomized patient-specific instrument may be configured to engage thetibial tray 22 and the femoral prosthetic component 14.

Returning to FIG. 1, the algorithm 10 includes process steps 38 and 40,in which an orthopaedic surgeon performs pre-operative planning of theorthopaedic surgical procedure to be performed on a patient. The processsteps 38 and 40 may be performed in any order or contemporaneously witheach other. In process step 38, a number of medical images of therelevant area of the patient are generated, including images of the bonyanatomy or joint and the previously-implanted primary prosthesis. Thoseimages may include, for example, an image 42 of the anterior portion ofthe patient's bones, which, as shown in FIG. 3, illustrates the positionthe primary femoral prosthetic component 14 on the distal end 16 of thepatient's femur 18 and the tibial tray 22 on the proximal end 24 of thepatient's tibia 26.

To do so, the orthopaedic surgeon or other healthcare provider mayoperate an imaging system to generate the medical images. The medicalimages may be embodied as any number and type of medical images capableof being used to generate a three-dimensional rendered model of thepatient's previously-implanted prosthesis and bony anatomy or relevantjoint. For example, the medical images may be embodied as any number ofcomputed tomography (CT) images, magnetic resonance imaging (MRI)images, or other three-dimensional medical images. Additionally oralternatively, as described in more detail below in regard to processstep 44, the medical images may be embodied as a number of X-ray imagesor other two-dimensional images from which a three-dimensional renderedmodel of the patient's previously-implanted prosthesis and relevant bonyanatomy may be generated.

In process step 40, the orthopaedic surgeon may determine any additionalpre-operative constraint data. The constraint data may be based on theorthopaedic surgeon's preferences, preferences of the patient,anatomical aspects of the patient, guidelines established by thehealthcare facility, or the like. For example, the constraint data mayinclude the orthopaedic surgeon's preference for the resection level ofthe patient's bone, femoral rotation of the revision prosthesis,revision prosthesis size preferences, tibial slope, and details of anyobserved patient abnormalities during primary postoperative care andmonitoring. In some embodiments, the orthopaedic surgeon's preferencesare saved as a surgeon's profile, which may used as default constraintvalues for further surgical plans.

In some embodiments, the medical images and the constraint data, if any,may be transmitted or otherwise provided to an orthopaedic surgicalinstrument vendor or manufacturer. The medical images and the constraintdata may be transmitted to the vendor via electronic means such as anetwork or the like. After the vendor has received the medical imagesand the constraint data, the vendor may process the images in processstep 44. In other embodiments, the images may be processed locally.

In process step 44, the medical images are processed to facilitate thedetermination of the bone cutting planes, implant sizing, andfabrication of the customized patient-specific orthopaedic surgicalinstrument as described in more detail below. For example, in processstep 46, the medical images may be converted to generatethree-dimensional images. For example, in embodiments wherein themedical images are embodied as a number of two-dimensional images, asuitable computer algorithm may be used to generate one or morethree-dimensional images from the number of two-dimensional images.Additionally, in some embodiments, the medical images may be generatedbased on an established standard such as the Digital Imaging andCommunications in Medicine (DICOM) standard. In such embodiments, anedge-detection, thresholding, watershead, or shape-matching algorithmmay be used to convert or reconstruct images to a format acceptable in acomputer aided design application or other image processing application.Further, in some embodiments, an algorithm may be used to account fortissue such as ligaments not discernable in the generated medicalimages. In such embodiments, any three-dimensional model of thepatient-specific instrument (see, e.g., process step 76 below) may bemodified according to such algorithm to increase the fit and function ofthe instrument.

In process step 48, the medical images and/or theconverted/reconstructed images from process step 46 may be processed todetermine a number of landmarks of the patient's bony anatomy and theimplanted knee prosthesis. To do so, the vendor may use any suitablealgorithm to process the images. Depending on the surgical procedure,the landmarks the bony anatomy may include, for example, the patient'sfemoral epicondyles, femoral intramedullary canal, tibial intramedullarycanal, fibula head, tibia tubercle, hip center, ankle center, and and/orother aspects of the patient's bony anatomy. In a revision surgery forone of the patient's knees, the joint line of the patient's other kneemay also be identified. What is meant herein by “joint line” inreference to the patient's bony anatomy is the line of contact betweenthe distal end of the patient's femur and the proximal end of thepatient's tibia.

Additionally, a number of landmarks of the implanted primary prosthesismay be determined from the medical images and/or theconverted/reconstructed images. Those landmarks may include, forexample, the most distal medial point, the most distal lateral point,most posterior medial point, and most posterior lateral point of theprimary femoral prosthetic component. The tibial plateau points may alsobe determined along with the most proximal medial point, most proximallateral point, most posterior medial point, and most posterior lateralpoint of the primary tibial prosthetic component such as, for example,the implanted tibial tray.

In the process step 50, the landmarks identified in process step 48 maybe used to determine the alignment of patient's bones and the implantedprimary prosthesis. For example, as shown in FIG. 4, a joint line 52 ofthe implanted primary prosthesis may be determined by locating the mostdistal medial point and the most distal lateral point of the primaryfemoral prosthetic component when the patient's leg is in extension. Inreference to knee prosthetic components, the term “joint line” refers tothe contact line between the prosthetic femoral component and theprosthetic tibial bearing of the knee prosthesis. As shown in FIG. 4,the joint line 52 is established by the most distal medial point 54 andthe most distal lateral point 56 of the femoral prosthetic component 14.

Other landmarks may be used to establish other aspects of the presentalignment of the patient's bone. For example, the ankle center may beused to locate and define the center of the patient's talus, and thecenter of the patient's talus may be used with the orientation of theprimary tibial tray 22 to establish the tibial mechanical axis 58. Thevarus angle 60 of the patient's tibia 26 may then be determined.

Similarly, the hip center may be used to establish the patient's femoralhead, which may be subsequently used with the orientation of the primaryfemoral prosthetic component 14 to establish the femoral mechanical axis62. As shown in FIG. 4, the valgus angle 64 may then be determined.Additionally, the location of the femoral anatomical axis 66 may becalculated by locating the center of the distal shaft (not shown) of theprimary femoral prosthetic component 14. As shown in FIG. 5, the femoralmedial and lateral epicondyles may be used to create the epicondylaraxis 70, which may be used to establish the femoral rotation of theprimary femoral prosthetic component 14.

In process step 50, a digital template 74 of the primary orthopaedicprosthesis may be overlaid onto one or more of the processed medicalimages, as shown in, for example, FIGS. 6 and 7. The vendor may use anysuitable algorithm to determine a recommended location and orientationof the orthopaedic prosthesis (i.e., the digital template) with respectto the patient's bone based on the processed medical images (e.g.,landmarks of the patient's bone defined in the images) and/or theconstraint data. Any one or more other aspects of the patient's bonyanatomy may also be used to determine the proper positioning of thedigital template. Additionally, the landmarks of the primary orthopaedicprosthesis identified in process step 48 may be used to determine theproper positioning of the digital template.

In process step 72, a surgical plan is generated. As part of thesurgical plan, the cutting planes of the patient's bone may bedetermined. The planned cutting planes are determined based on the type,size, and position of the orthopaedic prosthesis to be used during theorthopaedic surgical procedure, on the processed images such as specificlandmarks identified in the images, and on the constraint data suppliedin process steps 38 and 40. The type and/or size of the orthopaedicprosthesis may be determined based on the patient's anatomy and theconstraint data. For example, the constraint data may dictate the type,make, model, size, or other characteristic of the orthopaedicprosthesis.

The selection of the revision orthopaedic prosthesis may also bemodified based on the medical images. For example, as shown in FIGS. 6and 7, a digital template 74 of the revision orthopaedic prosthesis maybe overlaid onto one or more of the processed medical images. Thedigital template 74 may be a three-dimensional model of the revisionorthopaedic prosthesis, which accurately reproduces the dimensions ofthe actual prosthesis. The model may be included in a library of suchthree-dimensional models. The vendor may use any suitable algorithm todetermine a recommended location and orientation of the orthopaedicprosthesis (i.e., the digital template) with respect to the patient'sbone based on the processed medical images (e.g., landmarks of thepatient's bone defined in the images) and/or the constraint data.Additionally, any one or more other aspects of the patient's bonyanatomy may be used to determine the proper positioning of the digitaltemplate. As such, the surgeon and/or vendor may select a revisionorthopaedic prosthesis that is usable with the bony anatomy of thepatient and that matches the constraint data or preferences of theorthopaedic surgeon.

The digital template along with surgical alignment parameters may beused to generate the surgical plan document. The document may includethe revision implant's target rotation with respect to bony landmarkssuch as the femoral epicondyle, posterior condyles, and the mechanicalaxis as defined by the hip, knee, and/or ankle centers. The document mayalso include the planned target joint line for the revision orthopaedicprosthesis, the target valgus angle, and the target varus angle.

The planned cutting planes for the patient's bone(s) may then bedetermined based on the determined size, location, and orientation ofthe orthopaedic prosthesis. In addition, other aspects of the patient'sbony anatomy, as determined in process step 44, may be used to determineor adjust the planned cutting planes. For example, the determinedmechanical axis, landmarks, and/or other determined aspects of therelevant bones of the patient may be used to determine the plannedcutting planes.

In process step 76, a model of the customized patient-specificorthopaedic surgical instrument is generated. In some embodiments, themodel is embodied as a three-dimensional rendering of the customizedpatient-specific orthopaedic surgical instrument. In other embodiments,the model may be embodied as a mock-up or fast prototype of thecustomized patient-specific orthopaedic surgical instrument. Theparticular type of orthopaedic surgical instrument to be modeled andfabricated may be determined based on the orthopaedic surgical procedureto be performed, the constraint data, and/or the type of orthopaedicprosthesis to be implanted in the patient. As such, the customizedpatient-specific orthopaedic surgical instrument may be embodied as anytype of orthopaedic surgical instrument for use in the performance of anorthopaedic surgical procedure. For example, the orthopaedic surgicalinstrument may be embodied as a bone-cutting block, a drilling/pinningguide, a milling guide, and/or any other type of orthopaedic surgicaltool or instrument.

The particular shape of the customized patient-specific orthopaedicsurgical instrument is determined based on the planned location of theorthopaedic surgical instrument relative to the patient's bony anatomyand, in some embodiments, the implanted primary prosthesis. The locationof the customized patient-specific orthopaedic surgical instrument isdetermined based on the type and determined location of the orthopaedicprosthesis to be used during the orthopaedic surgical procedure. Thatis, the planned location of the customized patient-specific orthopaedicsurgical instrument relative to the patient's bony anatomy may beselected based on, in part, the planned cutting planes of the patient'sbone(s) as determined in step 72.

For example, in embodiments in which the customized patient-specificorthopaedic surgical instrument is embodied as a drilling/pinning guide(or hereinafter, simply a “pin guide”) for use in conjunction with apatient-universal cutting block, the location of the orthopaedicsurgical instrument is selected to position guide pins in the bone foruse with the patient-universal cutting block. The guide pins, when usedwith one or more customized alignment guides, may align the cuttingguide of the patient-universal cutting block with one or more of theplanned cutting planes determined in process step 72. Additionally, theplanned location of the orthopaedic surgical instrument may be based onthe identified landmarks of the patient's bone identified in processsteps 48 and 50.

In some embodiments, the particular shape or configuration of thecustomized patient-specific orthopaedic surgical instrument may bedetermined based on the planned location of the instrument relative tothe patient's bony anatomy. That is, the customized patient-specificorthopaedic surgical instrument may include a bone-contacting surfacehaving a negative contour that matches the contour of a portion of thebony anatomy of the patient such that the orthopaedic surgicalinstrument may be coupled to the bony anatomy of the patient in a uniquelocation, which corresponds to the pre-planned location for theinstrument. As described above, the customized patient-specificorthopaedic surgical instrument may also include a prosthesis-engagingsurface having a negative contour that matches the contour of a portionof the implanted primary prosthesis of the patient. The customizedpatient-specific orthopaedic surgical instrument may be configured tointerface with a patient-universal instrument to position thepatient-universal instrument in a preplanned location relative to thebone or bones of the patient. When the customized patient-specificorthopaedic surgical instrument is coupled to the patient's bonyanatomy, the implanted primary prosthesis, and/or patient-universalinstrument in the unique location, one or more guides (e.g., cutting ordrilling guide) may be aligned with one or more of the bone cuttingplane(s) as described above.

Referring back to FIG. 1, after the model of the customizedpatient-specific orthopaedic surgical instrument has been generated inprocess step 76, the model is validated in process step 78. The modelmay be validated by, for example, analyzing the rendered model whilecoupled to the three-dimensional model of the patient's anatomy toverify the correlation of cutting guides and planes, drilling guides andplanned drill points, and/or the like. Additionally, the model may bevalidated by transmitting or otherwise providing the model generated instep 78 to the orthopaedic surgeon for review. For example, inembodiments wherein the model is a three-dimensional rendered model, themodel along with the three-dimensional images of the patient's relevantbone(s) may be transmitted to the surgeon for review. In embodimentswherein the model is a physical prototype, the model may be shipped tothe orthopaedic surgeon for validation.

After the model has been validated in process step 78, the customizedpatient-specific orthopaedic surgical instrument is fabricated inprocess step 80. The customized patient-specific orthopaedic surgicalinstrument may be fabricated using any suitable fabrication device andmethod. Additionally, the customized patient-specific orthopaedicinstrument may be formed from any suitable material such as a metallicmaterial, a plastic material, or combination thereof depending on, forexample, the intended use of the instrument. The fabricated customizedpatient-specific orthopaedic instrument is subsequently shipped orotherwise provided to the orthopaedic surgeon. The surgeon performs theorthopaedic surgical procedure in process step 82 using the customizedpatient-specific orthopaedic surgical instrument. As discussed above,because the orthopaedic surgeon does not need to determine the properlocation of the orthopaedic surgical instrument intra-operatively, whichtypically requires some amount of estimation on part of the surgeon, theguesswork and/or intra-operative decision-making on part of theorthopaedic surgeon is reduced.

Referring now to FIGS. 8-10, a customized patient-specific orthopaedicsurgical instrument is shown as a femoral pin guide 100. In theillustrative embodiment, the pin guide 100 is configured to be coupledto the distal end 16 of the patient's femur 18 and the primary femoralprosthetic component 14 of the primary knee prosthesis 12. As describedin greater detail below, the femoral pin guide 100 is used to install apair of guide pins 102 in a location on the femur 18 that has beenpreplanned and customized for that particular patient. In theillustrative embodiment, the pin guide 100 is configured such that theguide pins 102 are inserted into the medial side of the distal end 16 ofthe patient's femur 18. It should be appreciated that in otherembodiments the pin guide 100 may be configured to insert the pins 102into the lateral side or anterior side of the patient's femur 18.

In the illustrative embodiment, the femoral pin guide 100 is devoid of acutting guide; as such, other cutting blocks are required to resect andshape the distal end 16 of the patient's femur 18 to receive a revisionfemoral prosthetic component. Those other cutting blocks may bepatient-universal cutting blocks such as, for example, a distal cuttingblock 104 (see FIG. 11) and a 4-in-1 cutting block 106 (see FIG. 14). Asdescribed in greater detail below, other customized patient-specificorthopaedic surgical instrument, such as an alignment bracket 108 (seeFIGS. 11-13) and alignment guide 110 (see FIGS. 14-15), may befabricated to engage the custom-located guide pins 102 and position theuniversal cutting blocks in preplanned positions and orientations. Suchan arrangement permits a certain degree of customization of the surgicalprocedure by customizing the placement of the guide pins 102 to thepatient's anatomy, while also enjoying the cost benefits associated withthe use of reusable patient-universal cutting blocks. It should also beappreciated that in other embodiments the guide pins 102 may be locatedsuch that the patient-universal guide blocks may be installed directlyon the guide pins 102. In yet other embodiments, the each cutting guideblock may be a customized patient-specific cutting guide blockconfigured to be installed on the guide pins 102.

As shown in FIG. 8, the pin guide 100 includes a main body 112configured to engage the primary femoral prosthetic component 14 of theprimary knee prosthesis 12 and a support body 114 configured to becoupled to the medial side of the distal end 16 of the patient's femur18. The pin guide 100 also includes arms 116, 118, which connect thebodies 112, 114. The pin guide 100 may be formed from a material such asa plastic or resin material. In some embodiments, the pin guide 100 maybe formed from a photo-curable or laser-curable resin. In one particularembodiment, the pin guide 100 is formed from a Vero resin using a rapidprototype fabrication process. It should be appreciated that in otherembodiments the pin guide 100 may be formed from other materials inother embodiments. For example, in another particular embodiment, thepin guide 100 is formed from a polyimide thermoplastic resin, such as anUltem resin. In the illustrative embodiment described herein, the pinguide 100 is embodied as a monolithic structure.

The main body 112 of the pin guide 100 includes a prosthesis-engagingsurface 120 and an outer surface 122 opposite the prosthesis-engagingsurface 120. The outer surface 122 is contoured to be gripped by thesurgeon or other user. As shown in FIG. 9, the prosthesis-engagingsurface 120 of the main body 112 includes a negative contour 124 that isconfigured to receive a portion of a medial condyle 126 (see FIG. 2) ofthe primary femoral component 14 having a corresponding contour. In theillustrative embodiment, the negative contour 124 of pin guide 100includes a curved inner surface 128 that is shaped to match the curvedcondyle surface 32 of the medial condyle 126. The customizedpatient-specific negative contour 124 of the prosthesis-engaging surface120 permits the pin guide 100 to be positioned on the patient's primaryfemoral component 14 (and hence the patient's femur 18) in a uniquepre-determined location and orientation, as described in greater detailbelow.

It should be appreciated that in other embodiments the customizedpatient-specific pin guide may be configured to engage other portions ofthe primary femoral prosthetic component. For example, the pin guidemight include a negative contour that is configured to receive a portionof a lateral condyle of the primary femoral component and/or a negativecontour that is configured to receive a portion of the trochleargeometry of the primary femoral component. In other embodiments, the pinguide might include a negative contour that is configured to receive aportion of the anterior flange of the primary femoral component.

The support body 114 of the pin guide 100 includes a bone-contacting orbone-facing surface 140 and an outer surface 142 opposite thebone-facing surface 140. As shown in FIG. 8, the bone-facing surface 140is a lateral surface configured to face the medial side of the distalend 16 of the patient's femur 18. The support body 114 has a number ofguide holes 144 extending therethrough. A removable drill bushing 146 islocked into each guide hole 144. As will be described below in greaterdetail, the removable drill bushings 146 may be installed in the pinguide 100 for use in a surgical procedure and then removed from the pinguide 100. Whereas the pin guide 100 is customized and may be disposedafter a single use on the patient for which it was made, the removeddrill bushings 146 may be sterilized and reused in a subsequent surgicalprocedure.

As shown in FIG. 9, the bone-facing surface 140 of the support body 114is substantially smooth. It should be appreciated that in otherembodiments the bone-facing surface 140 may include a negative contourconfigured to receive a portion of the distal end 16 of the patient'sfemur 18 having a corresponding contour. In such embodiments, thenegative contour of the bone-facing surface 140, in conjunction with thenegative contour 124 of the prosthesis-engaging surface 120, permits thepositioning of the pin guide 100 on the patient's femur 18 in a uniquepredetermined location and orientation.

As described above, a pair of removable drill bushings 146 may beattached to the pin guide 100. As shown in FIG. 8, each removable drillbushing 146 includes an elongated bore 148 that extends therethrough.The bore 148 is sized to receive a drill such that the patient's femurmay be pre-drilled prior to installation of the guide pins 102. In theillustrative embodiment, each end of the bore 148 is countersunk. Eachremovable drill bushing 146 also includes a head 150 that is contouredto be gripped by a surgeon's fingers. The countersunk opening on thedrill bushing's head 150 functions as a lead-in to facilitationinsertion of the drill and the guide pins 102 into the bore 148.

A post 152 of the removable drill bushing 146 extends away from the head150 and includes a locking flange 154 formed on the outer surfacethereof. The locking flange 154 is utilized to lock the post 152 withinone of the guide holes 144 of the pin guide 100. Specifically, as shownin FIG. 10, a locking slot 156 is formed in the support body 114proximate to each of the guide holes 144. In the illustrativeembodiment, the removable drill bushings 146 and locking slots 156utilize a cam lock arrangement to secure the bushings 146 to the supportbody 114.

As shown in FIG. 9, the locking slot 156 includes two elongated channels158 positioned on opposite sides of the guide hole 144 and an annularrecess 160 formed within the support body 114. The outer ends of thechannels 158 open to the outer surface 142 of the support body 114, withthe inner ends of the channels 158 opening into the annular recess 160.A shoulder 162 defines the lateral side of the locking slot's annularrecess 160. In the illustrative embodiment, the shoulder 162 is embodiedas an angled cam surface. As will be described below, the locking flange154 of the removable drill bushing 146 engages the cam surface to lockthe removable drill bushing 146 to the pin guide 100.

The locking flange 154 is embodied as a pair of tabs 164 extendingoutwardly from opposite sides of its post 152. The tabs 164 are sizedand positioned to be received into the respective channels 158 of thepin guide's locking slot 156. Specifically, to lock the removable drillbushing 146 to the pin guide 100, each of the tabs 164 is first alignedwith one of the channels 158 and thereafter advanced into the channels158. When the tabs 164 have been advanced into the channels 158 farenough to clear the shoulder 162, the head 150 of the removable drillbushing 146 may be rotated approximately 90 degrees, thereby alsorotating the tabs 164. Such rotation of the tabs 164 removes the tabsfrom alignment with the channels 158 such that the tabs 164 are capturedwithin the annular recess 160. Such rotation also causes the cam surface166 of the tabs 164 to engage the cam surface of the shoulder 162 tolock the removable drill bushing 146 to the pin guide 100.

To unlock the removable drill bushing 146 from the pin guide 100, thehead 150 of the removable drill bushing 146 may be rotated in theopposite direction it was rotated during installation to a position inwhich the tabs 164 are aligned with the channels 158. Once the tabs 164are aligned in such a manner, the post 152 of the removable drillbushing 146 may be removed from the guide hole 144, therebydisassembling the removable drill bushing 146 from the pin guide 100.

It should be appreciated that in other embodiments the removable drillbushings 146 and locking slots 156 may utilize other lockingarrangements to secure the bushings 146 to the support body 114. Forexample, the bushings 146 may include external threads that threadinglyengage the locking slots 156.

Referring now to FIGS. 11-14, a patient-universal distal cutting block104 is shown with another customized patient-specific orthopaedicsurgical instrument 108. In the illustrative embodiment, the customizedpatient-specific orthopaedic surgical instrument 108 is embodied as analignment guide or bracket 108, which engages the custom-located guidepins 102 to position the distal cutting block 104 in a preplannedposition and orientation. As shown in FIG. 11, the distal cutting block104 includes a posterior side wall 170 that confronts the anteriorsurface of the femur 18 when the distal cutting block 104 positionedthereon. The distal cutting block 104 also includes an anterior sidewall 172 positioned opposite the posterior side wall 170. A number ofguide pin holes 174 extend through the side walls 170, 172. In theillustrative embodiment, the distal cutting block 104 includes fourdifferent pairs of guide pin holes 174.

The distal cutting block 104 includes a number of distal cutting guides176, 178, 180 that may be used to guide the resection of the distal end16 of the patient's femur 18. In the illustrative embodiment, eachcutting guide 176 is embodied as a captured cutting guide (i.e., it isclosed on all sides so as to capture a saw blade therein) and includesan elongated slot extending in the medial/lateral direction. As shown inFIG. 11, the distal cutting block 104 has three distal cutting guides176, 178, 180 extending through the side walls 170, 172. Each distalcutting guide defines a resection plane 182, which extends through thedistal end 16 of the patient's femur 18 when the distal cutting block104 is positioned thereon. Each of the distal cutting guides 176, 178,180 is sized and shaped to receive the blade (not shown) of a surgicalsaw or other cutting instrument and orient the blade to resect thedistal surfaces of the patient's femur during an orthopaedic surgicalprocedure. In that way, the cutting guides 176, 178, 180 may be used bythe orthopaedic surgeon during the resection of the patient's femur and,more specifically, during the resection of the distal surfaces of thepatient's femur 18. Because the cutting guides 176, 178, 180 are used toresect the distal surfaces of the patient's femur, the amount ofmaterial removed by each cutting guide affects the position of the jointline of the revision orthopaedic prosthesis.

For example, the cutting guide 176 of the cutting block 104 is thebaseline or “zero” setting. If the surgeon desires to elevate the jointline of the revision orthopaedic prosthesis (or use a prosthetic augmentcomponent), more bone may be removed from the distal end 16 of the femur18 than would be removed by use of the zero setting. To do so, thesurgeon may use the cutting guide 178, which is spaced apart from thecutting guide 176 by approximately four millimeters in the illustrativeembodiment. The cutting guide 178 is thus the “+4 mm” setting in theillustrative embodiment. If the surgeon desires to remove still morebone (and hence further elevate the joint line), the surgeon may use thecutting guide 180, which is spaced apart from the cutting guide 176 byapproximately four millimeters and is thus the “+8 mm” setting. In otherembodiments, the distal cutting block 104 may include any number ofcutting guides, which may be spaced apart by an amount greater than orless than four millimeters.

As described above, the customized patient-specific orthopaedic surgicalinstrument 108 (i.e., the alignment bracket 108) is configured to engagethe distal cutting block 104 and the custom-located guide pins 102 toposition the cutting block 104 in a preplanned location and orientation.In the illustrative embodiment, the alignment bracket 108 has anL-shaped body 190 that is configured to engage the guide pins 102 and amounting flange 192 configured to be received in one of the cuttingguides 176, 178, 180 of the distal cutting block 104. The alignmentbracket 108 may be formed from a material such as a plastic or resinmaterial. In some embodiments, the alignment bracket 108 may be formedfrom a photo-curable or laser-curable resin. In one particularembodiment, the alignment bracket 108 is formed from a Vero resin usinga rapid prototype fabrication process. It should be appreciated that inother embodiments the alignment bracket 108 may be formed from othermaterials in other embodiments. For example, in another particularembodiment, the alignment bracket 108 is formed from a polyimidethermoplastic resin, such as an Ultem resin. In the illustrativeembodiment described herein, the alignment bracket 108 is embodied as amonolithic structure.

As shown in FIG. 12, the body 190 of the alignment bracket 108 includesan anterior arm 194 and a medial arm 196 extending away from theanterior arm 194. The anterior arm 194 has an inner surface 198 thatfaces the distal cutting block 104 and an outer surface 200 positionedopposite the inner surface 198. The inner surface 198 includes anegative contour 202 that is shaped to match a corresponding contour ofthe distal cutting block 104. In the illustrative embodiment, thecontour 202 of the alignment bracket 108 is curved to match a curvedsection of the anterior side wall 172 of the distal cutting block 104.

The mounting flange 192 of the alignment bracket 108 has a base 204 thatis attached to the inner surface 198 of the anterior arm 194 and a tip206 that is spaced apart from the base 204. As shown in FIG. 13, themounting flange 192 has a thickness 208 defined between a pair ofsubstantially planar surfaces 210, 212. In the illustrative embodiment,the thickness 208 is slightly larger than each opening 214 of thecutting guides 176, 178, 180 of the distal cutting block 104. In thatway, when the flange 192 of the alignment bracket 108 is inserted intoone of the cutting guides 176, 178, 180, the surfaces 210, 212 engagethe walls of that cutting guide to retain the flange 192 therein,thereby securing the alignment bracket 108 to the cutting block 104. Inother embodiments, the mounting flange 192 and/or the body 190 mayinclude a tab, lug, or other feature to secure the alignment bracket 108to the cutting block 104.

As shown in FIGS. 12-13, the medial arm 196 of the alignment bracket 108extends posteriorly from the anterior arm 194. The medial arm 196 issized to engage the guide pins 102 when the alignment bracket 108 issecured to the cutting block 104 and the cutting block 104 is properlypositioned relative to the patient's femur 18. As shown in FIG. 12, themedial arm 196 has an anterior end 216 attached to the anterior arm 194and a posterior end 218. The medial arm 196 has a length 220 definedbetween the ends 216, 218, which is selected to permit the medial arm196 to engage the pair of custom-located guide pins 102, whichcorresponds to the anterior-posterior width of the distal end 16 of thepatient's femur 18.

As shown in FIG. 13, the medial arm 196 has a lower surface 222configured to engage the guide pins 102 and an upper surface 224positioned opposite the lower surface 222. In the illustrativeembodiment, the surfaces 222, 224 are substantially planar. Thealignment bracket 108 has a distance 226 defined between the lowersurface 222 and the lower surface 210 of the mounting flange 192. Thedistance 226 is customized to a particular patient based on the plannedlocation of the joint line of the revision orthopaedic prosthesis. Thedistance 226 is smaller when greater elevation of the joint line of therevision orthopaedic prosthesis is desired (i.e., when a larger distalcut of the distal end 16 of the femur is planned). For example, when itis desired to use the cutting guide 180 of the cutting block 104 (i.e.,the “+8 mm” setting) to elevate the joint line, the distance 226 may beset to position the mounting flange 192 closer to the lower surface 222such that the flange 192 may be received in the cutting guide 180.

In other embodiments, less elevation of the joint line of the revisionorthopaedic prosthesis may be desired. In such embodiments, the distance226 may be greater such that less material is removed from the distalend 16 of the femur 18. Thus, when it is desired to use the cuttingguide 176 of the cutting block (i.e., the “zero” setting), the distance226 may be set to position the mounting flange 192 farther from thelower surface 222. In that way, the flange 192 may be received in thecutting guide 176 to secure the alignment bracket 108 to the cuttingblock 104.

As shown in FIG. 14, the alignment bracket 108 has an indicator 228 thatshows the position of the mounting flange 192. In the illustrativeembodiment, the indicator 228 is a tab or pointer 230 extending from theanterior arm 194. When the alignment bracket 108 is secured to thecutting block 104, the pointer 230 indicates the cutting guide slot inwhich the mounting flange 192 is received.

Referring now to FIGS. 15-16, a patient-universal 4-in-1 cutting block106 is shown with another customized patient-specific orthopaedicsurgical instrument 110. In the illustrative embodiment, the customizedpatient-specific orthopaedic surgical instrument 110 is embodied as analignment guide 110, which engages the custom-located guide pins 102 toposition the 4-in-1 cutting block 106 in a preplanned position andorientation. As shown in FIG. 15, the 4-in-1 cutting block 106 includesa body 238 having an outer surface 240, a bone-engaging surface 242positioned opposite the outer surface 240, a medial side wall 244extending between the surfaces 240, 242, and a lateral side wall 246positioned opposite the medial side wall 244. In the illustrativeembodiment, the bone-engaging surface 242 of the 4-in-1 cutting block106 confronts the distal surface of the femur 18.

The 4-in-1 cutting block 106 has an anterior cutting guide 248 formednear its anterior end 250 and a plurality of posterior cutting guides252 formed near its posterior end 254. The anterior cutting guide 248 isan elongated slot extending in the medial/lateral direction and isembodied as a captured cutting guide (i.e., it is closed on all sides soas to capture a saw blade therein). The anterior cutting guide 248extends through the entire thickness of the 4-in-1 cutting block106—that is, the anterior cutting guide 248 extends through the cuttingblock's outer surface 240 and its bone-engaging surface 242. The cuttingguide 248 defines a resection plane 256, which extends through thedistal end 16 of the patient's femur 18 when the cutting block 106 ispositioned thereon The anterior cutting guide 248 is sized and shaped toreceive the blade (not shown) of a surgical saw or other cuttinginstrument and orient the blade to resect the anterior surface of thepatient's femur during an orthopaedic surgical procedure.

Each posterior cutting guide 252 includes a pair of elongated slotsextending in the medial/lateral direction. Each is embodied as apartially captured cutting guide (i.e., each is closed on three sides soas to capture a saw blade therein). Each posterior cutting guide 252extends through the entire thickness of the 4-in-1 cutting block106—that is, each posterior cutting guide 252 extends through thecutting block's outer surface 240 and its bone-engaging surface 242.Each cutting guide 252 defines a resection plane 258, which extendsthrough the distal end 16 of the patient's femur 18 when the cuttingblock 106 is positioned thereon. Each cutting guide 252 is sized andshaped to receive the blade (not shown) of a surgical saw or othercutting instrument and orient the blade to resect the posterior surfacesof the patient's femur during an orthopaedic surgical procedure.

The 4-in-1 cutting block 106 has a pair of chamfer cutting guides 260,262 formed near its middle. Specifically, the chamfer cutting guides260, 262 are located posteriorly of the anterior cutting guide 248 andanteriorly of the posterior cutting guides 252. As shown in FIG. 15, thechamfer cutting guide 260 includes a pair of elongated slots extendingin the medial/lateral direction. The chamfer cutting guide 260 isembodied as a partially captured cutting guide (i.e., it is closed onthree sides so as to capture a saw blade therein). The chamfer cuttingguide 260 extends through the entire thickness of the 4-in-1 cuttingblock 106—that is, the chamfer cutting guide 260 extends through thecutting block's outer surface 240 and its bone-engaging surface 242. Thechamfer cutting guide 260 defines a resection plane 264, which extendsthrough the distal end 16 of the patient's femur 18 when the cuttingblock 106 is positioned thereon. The chamfer cutting guide 260 is sizedand shaped to receive the blade (not shown) of a surgical saw or othercutting instrument and orient the blade to perform an anterior chamfercut of the patient's femur during an orthopaedic surgical procedure.

Similarly, the chamfer cutting guide 262 includes a pair of elongatedslots extending in the medial/lateral direction. The chamfer cuttingguide 262 is embodied as a partially captured cutting guide (i.e., it isclosed on three sides so as to capture a saw blade therein). The chamfercutting guide 262 extends through the entire thickness of the 4-in-1cutting block 106—that is, the chamfer cutting guide 262 extends throughthe cutting block's outer surface 240 and its bone-engaging surface 242.The chamfer cutting guide 262 defines a resection plane 266, whichextends through the distal end 16 of the patient's femur 18 when thecutting block 106 is positioned thereon. The chamfer cutting guide 262is sized and shaped to receive the blade (not shown) of a surgical sawor other cutting instrument and orient the blade to perform a posteriorchamfer cut of the patient's femur during an orthopaedic surgicalprocedure.

The 4-in-1 cutting block 106 also includes a bushing 270 that ismoveable relative the body 238 of the 4-in-1 cutting block 106. As shownin FIG. 15, the bushing 270 is positioned in an elongated slot 272extending in the anterior-posterior direction. The elongated slot 272extends through the entire thickness of the 4-in-1 cutting block106—that is, the elongated slot 272 extends through the cutting block'souter surface 240 and its bone-engaging surface 242. The bushing 270 hasa cylindrical body 274 that is sized to be received in the slot 272 andmay be moved along the longitudinal axis 276 of the slot 272 between theanterior and posterior ends of the slots 272. The bushing 270 alsoincludes a bore 278 that extends through the cylindrical body 274. Asdescribed in greater detail below, the bore 278 is sized to receive anintramedullary shaft 310 (see FIG. 29). The 4-in-1 cutting block 106also includes a locking mechanism (not shown) configured to lock thebushing 270 at any position along the axis 276 of the slot 272. Itshould be appreciated that in other embodiments the movable bushing 270may be omitted and the bushing 270 may be integrally formed with theblock 106 or otherwise fixed relative to it.

As described above, the customized patient-specific orthopaedic surgicalinstrument 110 (i.e., the alignment guide 110) is configured to engagethe 4-in-1 cutting block 106 and the custom-located guide pins 102 toposition the cutting block 106 in a preplanned location and orientation.In the illustrative embodiment, the alignment guide 110 includes a body280 configured to engage the guide pins 102 and a pair of posts 282, 284that extend laterally from the body 280. The alignment guide 110 may beformed from a material such as a plastic or resin material. In someembodiments, the alignment guide 110 may be formed from a photo-curableor laser-curable resin. In one particular embodiment, the alignmentguide 110 is formed from a Vero resin using a rapid prototypefabrication process. It should be appreciated that in other embodimentsthe alignment guide 110 may be formed from other materials in otherembodiments. For example, in another particular embodiment, thealignment guide 110 is formed from a polyimide thermoplastic resin, suchas an Ultem resin. In the illustrative embodiment described herein, thealignment guide 110 is embodied as a monolithic structure.

The body 280 of the guide 110 includes a bone-facing surface 286 and anouter surface 288 positioned opposite the bone-facing surface 286. Inthe illustrative embodiment, the bone-facing surface is the lateralsurface of the body 280 and the outer surface 288 is medial surface. Thealignment guide 110 has a pair of guide pin holes 290 that extendthrough the entire thickness of the body 280—that is, each hole 290extends through the cutting block's outer surface 288 and itsbone-facing surface 286. The guide pin holes 290 are sized andpositioned to receive the custom-located guide pins 102 such that thebody 280 may be positioned on the guide pins 102 during the orthopaedicsurgical procedure.

As shown in FIG. 16, the post 282 of the alignment guide 110 extendsfrom the body 280 to a tip 292. Similarly, the other post 284 of theguide 110 extends from the body 280 to a tip 294. The tips 292, 294 haveblock-facing or block-engaging surfaces 296, 298, respectively, that areconfigured to engage the medial side wall 244 of the 4-in-1 cuttingblock 106. As described in greater detail below, the posts 282, 284cooperate to define the femoral rotation of the cutting block 106 andhence the preplanned rotation of revision femoral component.

The alignment guide 110 also includes a marking 300 that indicates thepreplanned anterior-posterior position of the 4-in-1 cutting block 106.As shown in FIG. 16, the marking 300 is embodied as an elongated tab 302extending outwardly from the anterior surface 304 of the body 280. Whenthe alignment guide 110 is positioned on the custom-located guide pins102 and engages with the cutting block 106, the surgeon may align theanterior openings 306 of the chamfer cutting guides 260, 262 with themarking 300 to locate the cutting block 106 in the preplannedanterior-posterior position, as described in greater detail below.

Referring now to FIGS. 17-32, a surgeon may use the customizedpatient-specific femoral pin guide 100 to install a pair of guide pins102 in locations on the femur 18 that have been customized for thatparticular patient. A customized patient-specific alignment bracket 108may be secured to a patient-universal distal cutting block 104 andengaged with the custom-located pins 102 to locate the distal cuttingblock 104 in a unique preplanned orientation and position relative tothe patient's femur 18. Thereafter, the distal cutting block 104 may beused to resect the distal surfaces of the patient's femur 18. Acustomized patient-specific alignment guide 110 may be secured to apatient-universal 4-in-1 cutting block 106 and installed on thecustom-located pins 102 to locate the 4-in-1 cutting block 106 in aunique preplanned orientation and position relative to the patient'sfemur 18. Thereafter, the 4-in-1 cutting block 106 may be used to resectthe anterior, posterior, and chamfer surfaces of the patient's femur 18.Such an arrangement permits a certain degree of customization of thesurgical procedure by customizing the placement of the guide pins 102 tothe patient's anatomy, while also enjoying the cost benefits associatedwith the use of reusable patient-universal cutting blocks.

As shown in FIG. 17, the surgical procedure commences with assembly ofthe customized patient-specific surgical instrument 100 on a prep tableor other part of the surgery room. To do so, the surgeon first obtains acustomized patient-specific pin guide 100 that was fabricated for theparticular patient being treated by the surgeon. The pin guide 100, thealignment bracket 108, and the alignment guide 110 are fabricated in themanner described above in regard to FIGS. 1-7. Once the customizedpatient-specific pin guide 100 has been obtained, the surgeon then takesa pair of the sterilized removable drill bushings 146 and installs themin the pin guide 100. In particular, the surgeon may obtain a pair ofthe removable drill bushings 146 from a previous procedure (after beingsterilized) or new drill bushings 146 (from the manufacturer'ssterilized packaging). Thereafter, the surgeon inserts the post 152 ofone of the drill bushings 146 into one of the guide holes 144 formed inthe pin guide 100 and rotates the head 150 of the drill bushing 146 sothat the tabs 164 are captured within the annular recess 160, asdescribed above. The surgeon then obtains the other drill bushing 146and installs it in the pin guide's other guide hole 144 in a similarmanner.

As shown in FIGS. 18-19, the assembled customized patient-specific pinguide 100 is then coupled to the primary femoral prosthetic component 14on the distal end 16 of the patient's femur 18. Because theprosthesis-engaging surface 120 of the pin guide 100 includes thenegative contour 124, the pin guide 100 is coupled to the primaryfemoral prosthetic component 14 (and hence the patient's femur 18) in apre-planned, unique position and orientation. As shown in FIG. 19, themedial condyle 126 of the primary femoral component 14 is capturedwithin the main body 112 of the pin guide 100. When so coupled, the arms116, 118 extend around the distal end 16 of the patient's femur 18 toposition the support body 114 on the medial side of the patient's femur18. As shown in FIG. 18, the elongated bores 148 of the drill bushings146 extend in the medial/lateral direction away from the medial surfaceof the patient's femur 18.

The surgeon then installs the guide pins 102. To do so, the surgeonfirst drills pilot holes in the patient's femur by advancing a drill(not shown) through the guide bore 148 of each of the drill bushings146. The surgeon then inserts a guide pin 102 through the guide bore 148of each of the drill bushings 146 and into the drilled pilot holes. Asshown in FIG. 20, the guide pins 102 are installed in the patient'sfemur in customized, patient-specific locations created by use of thecustomized, patient-specific pin guide 100. It should be appreciatedthat if the guide pins 102 are self-tapping pins, pre-drilling of thepatient's femur is not necessary.

As shown in FIG. 21, once the guide pins 102 are installed in thepatient's femur 18 in the customized, patient-specific locations by useof the pin guide 100, the drill bushings 146 are removed. Specifically,the surgeon first grips the head 150 of one of the removable drillbushing 146 and rotates it in the direction opposite the rotation duringinstallation. The surgeon rotates the head 150 to a position in whichthe tabs 164 are aligned with the channels 158. Once the tabs 164 arealigned in such a manner, the post 152 of the removable drill bushing146 may be removed from the guide hole 144, thereby disassembling theremovable drill bushing 146 from the pin guide 100. The surgeon thenremoves the other drill bushing 146 from the pin guide's other guidehole 144 in a similar manner. In the illustrative embodiment, the drillbushings 146 are not disposed of, but rather may be retained andsterilized for use in a subsequent surgical procedure in combinationwith a customized patient-specific pin guide 100 that has beenfabricated for another patient.

As shown in FIGS. 22 and 23, with the drill bushings 146 removed, thepin guide 100 is then de-coupled and removed from the primary femoralcomponent 14 and hence the patient's femur 18. In doing so, the guidepins 102 are left behind in the patient's femur 18 in the customized,patient-specific locations created by use of the pin guide 100. Thesurgeon may then insert a canal reaming tool (not shown) or broach (notshown) into the distal end 16 of the patient's femur 18 to preparemedullary canal. One exemplary method of performing those operations isshown and described in SIGMA® Revision and M.B.T. Revision Tray SurgicalTechnique published 2008 by DePuy Orthopaedics, Inc., which is expresslyincorporated herein by reference. The surgeon may then position anintramedullary shaft 310 in the medullary canal as shown in FIG. 24.

As shown in FIG. 25, the surgeon may then attach a femoral locatingdevice 312 to the shaft 310. Using the surgical plan developed withalgorithm 10, the surgeon may use the locating device 312 to set thepreplanned valgus angle and right/left knee indication. The surgeon maythen position the distal cutting block 104 on the locating device 312,as shown in FIG. 26.

The surgeon may attach the alignment bracket 108 to the distal cuttingblock 104 before or after the cutting block 104 is positioned on thelocating device 312. To do so, the mounting flange 192 is aligned withthe desired cutting guide of the distal cutting block 104 as shown inFIG. 26. In the illustrative embodiment, the desired cutting guide isthe cutting guide 180, which is the “+8 mm” setting of the distalcutting block 104. The alignment bracket 108 may then be moved towardthe cutting block 104 to advance the tip 206 of the mounting flange 192into the anterior opening 214 of the cutting guide 180 and position theanterior side wall 172 of the block 104 in the negative contour 202 ofthe bracket 108. As described above, the surfaces 210, 212 of themounting flange 192 engage the walls of the cutting guide 180 to retainthe flange 192 therein, thereby securing the alignment bracket 108 tothe cutting block 104, as shown in FIG. 27.

The intramedullary shaft 310 extends along an anatomical axis 314 of thepatient's femur 18. The locating device 312 (and hence the cutting block106) may then be advanced along the shaft 310 (and hence the axis 314)toward the distal end 16 of the patient's femur 18. When the lowersurface 222 of the alignment bracket 108 engages the custom-locatedguide pins 102, the distal cutting block 104 is located in thepreplanned position relative to the patient's femur 18. As shown in FIG.28, additional guide pins 316 may be advanced into the guide pin holes174 of the distal cutting block 104 to secure the block 104 to thedistal end 16 of the patient's femur 18.

When the block 104 is secured to the femur 18, the alignment bracket 108may be removed. The surgeon may use the distal cutting block 104 toresect the distal surfaces of the patient's femur 18. To do so, thesurgeon advances a bone saw blade into the cutting guide 180 and cutsthe femur. As described above, the amount of bone removed with thedistal cutting block 104 determines the final location or elevation ofthe joint line of the revision orthopaedic prosthesis. If need be, thesurgeon may reposition the cutting block 104 on the guide pins 316 byusing a different pair of guide pin holes to perform a second cut toremove more bone. Once the distal surfaces of the patient's femur 18have been resected, the surgeon may then continue with the surgicalprocedure.

As shown in FIG. 29, the locating device 312, the distal cutting block104, and the additional guide pins 316 may be removed after the distalcut is performed. In doing so, the custom-located guide pins 102 areleft behind in the patient's femur 18. The surgeon may then position the4-in-1 cutting block 106 on the intramedullary shaft 310. To do so, thesurgeon aligns the bore 278 of the block's bushing 270 with the shaft310 and advances the block 106 toward the patient's femur 18 until thebone-engaging surface 242 contacts the distal surfaces of the patient'sfemur 18.

The surgeon may install the alignment guide 110 on the custom-locatedguide pins 102 by aligning the guide pin holes 290 with the guide pins102 and advancing the body 280 of the guide 110 over the guide pins 102.As shown in FIG. 30, the alignment guide 110 is advanced along the guidepins 102 to engage the tips 292, 294 of the posts 282, 284 with themedial side wall 244 of the cutting block 106. The engagement betweenthe tips 292, 294 of the guide 110 and the side wall 244 of the block106 causes the block 106 to rotate about the shaft 310 in the directionindicated by arrow 318 in FIG. 31. The side wall 244 is thereby broughtflush with the block-engaging surfaces 296, 298 of the tips 292, 294.The amount of rotation of the block 106 about the shaft 310 correspondsto the preplanned femoral rotation of the revision femoral component.

The surgeon may then move the 4-in-1 cutting block 106 relative to theshaft 310 (and hence the femur 18) in the anterior/posterior directionindicated by arrow 320 in FIG. 31. To do so, the surgeon grasps theblock 106 and moves block 106 relative to the bushing 270. When theanterior openings 306 of the chamfer cutting guides 260, 262 with themarking 300 of the alignment guide 110, the cutting block 106 is locatedin the preplanned anterior-posterior position and may be locked intoposition. The alignment guide 110 may then be removed, and the surgeonmay use the cutting block 106 to resect the anterior, posterior, andchamfer surfaces of the patient's femur 18. To do so, the surgeonadvances a bone saw blade into the anterior cutting guide 248, theanterior chamfer guide 260, the posterior chamfer guide 262, and thedesired posterior cutting guide 252 and cuts the femur. Once the distalend 16 of the patient's femur 18 has been resected as shown in FIG. 32,the surgeon may then continue with the surgical procedure to implant therevision orthopaedic prosthesis.

Referring now to FIGS. 33-35, another embodiment of a femoral pin guide(hereinafter pin guide 400) is shown. Like the pin guide 100, the pinguide 400 is configured to be coupled to the distal end 16 of thepatient's femur 18 and the primary femoral prosthetic component 14 ofthe primary knee prosthesis 12. The femoral pin guide 400 is used toinstall a pair of guide pins 102 in a location on the femur 18 that hasbeen preplanned and customized for that particular patient. In theillustrative embodiment, the pin guide 400 is configured such that theguide pins 102 are inserted into the anterior side of the distal end 16of the patient's femur 18. The femoral pin guide 400 is devoid of acutting guide; as such, like the pin guide 100, other cutting blocks arerequired to resect and shape the distal end 16 of the patient's femur 18to receive a revision femoral prosthetic component.

As shown in FIG. 33, the pin guide 400 includes a body 402 configured toengage the primary femoral prosthetic component 14 of the primary kneeprosthesis 12. The pin guide 400 may be formed from a material such as aplastic or resin material. In some embodiments, the pin guide 400 may beformed from a photo-curable or laser-curable resin. In one particularembodiment, the pin guide 400 is formed from a Vero resin using a rapidprototype fabrication process. It should be appreciated that in otherembodiments the pin guide 400 may be formed from other materials inother embodiments. For example, in another particular embodiment, thepin guide 400 is formed from a polyimide thermoplastic resin, such as anUltem resin. In the illustrative embodiment described herein, the pinguide 400 is embodied as a monolithic structure.

The body 402 of the pin guide 400 includes a posterior surface 404 andan outer surface 406 opposite the posterior surface 404. As shown inFIG. 34, the posterior surface 404 includes prosthesis-facing orengaging surface 408 and a bone-facing or engaging surface 410. Theprosthesis-engaging surface 408 includes a negative contour 412 that isconfigured to receive a portion of a medial condyle 126 of the primaryfemoral component 14 having a corresponding contour and a negativecontour 414 that is configured to receive a portion of a lateral condyle416 (see, e.g. FIG. 37) of the primary femoral component 14 having acorresponding contour. In the illustrative embodiment, the negativecontours 412, 414 of pin guide 400 include curved inner surfaces 418,420, respectively, that are shaped to match the curved condyle surfaces32, 34 of the medial condyle 126 of the lateral condyle 416.

The bone-engaging surface 410 of the pin guide 400 includes a negativecontour 424 configured to receive a portion of the patient's femur 18having a corresponding contour 426. In the illustrative embodiment, thenegative contour 424 includes a unique plurality of depressions andridges 428 that match a corresponding plurality of depressions andridges of the corresponding contour 426 of the patient's femur 18. Assuch, the negative contour 424 of the bone-engaging surface 410, inconjunction with the negative contours 412, 414 of theprosthesis-engaging surface 408, permits the pin guide 100 to bepositioned on the patient's femur 18 in a unique predetermined locationand orientation, as shown in FIG. 35.

The pin guide 400 also has a pair of metallic bushings 430 that aresecured to the body 402. As shown in FIGS. 33-35, each bushing 430extends through the thickness of the body 402—that is, each bushing 430extends through the pin guide's posterior surface 404 and outer surface406. As shown in FIG. 35, each bushing 430 includes an elongated bore432 that extends therethrough. The bore 432 is sized to receive a drillsuch that the patient's femur may be pre-drilled prior to installationof the guide pins 102. Each bore 432 is also sized to receive acorresponding guide pin 102, as shown in FIG. 35. It should beappreciated that in other embodiments the pin guide 400 may beconfigured for use with removable drill bushings similar to thosedescribed above in regard to the femoral pin guide 100.

The metallic components described herein may be secured to the polymerpin guide in a number of different manners. For example, the metalliccomponents may be overmolded to the polymer guide or otherwise securedto it as part of the molding process of the guide. The metalliccomponents may also be welded to the guide or secured to it with anadhesive. Other methods of securing the metallic components may also beemployed.

Referring now to FIGS. 36-37, another embodiment of a femoral pin guide(hereinafter pin guide 500) is shown. Like the pin guides 100 and 400,the pin guide 500 is configured to be coupled to the distal end 16 ofthe patient's femur 18 and the primary femoral prosthetic component 14of the primary knee prosthesis 12. The femoral pin guide 500 is used toinstall a pair of guide pins 102 in a location on the femur 18 that hasbeen preplanned and customized for that particular patient. In theillustrative embodiment, the pin guide 500 is configured such that theguide pins 102 are inserted into the lateral side of the distal end 16of the patient's femur 18. As shown in FIG. 36, the femoral pin guide500 includes a cutting guide 502 that may be used to resect thepatient's femur 18.

As shown in FIG. 36, the pin guide 500 includes a body 504 configured toengage the patient's femur 18 and an arm 506 configured to engage theprimary femoral prosthetic component 14 of the primary knee prosthesis12. The pin guide 500 may be formed from a material such as a plastic orresin material. In some embodiments, the pin guide 500 may be formedfrom a photo-curable or laser-curable resin. In one particularembodiment, the pin guide 500 is formed from a Vero resin using a rapidprototype fabrication process. It should be appreciated that in otherembodiments the pin guide 500 may be formed from other materials inother embodiments. For example, in another particular embodiment, thepin guide 500 is formed from a polyimide thermoplastic resin, such as anUltem resin. In the illustrative embodiment described herein, the pinguide 500 is embodied as a monolithic structure.

The body 504 of the pin guide 500 includes a bone-facing orbone-engaging surface 508 and an outer surface 510 opposite thebone-engaging surface 508. The bone-engaging surface 508 of the pinguide 500 includes a negative contour 512 configured to receive aportion of the patient's femur 18 having a corresponding contour 514(see FIG. 37). In the illustrative embodiment, the negative contour 512includes a unique plurality of depressions and ridges 516 that match acorresponding plurality of depressions and ridges of the correspondingcontour 514 of the patient's femur 18. The pin guide 500 also has anumber of metallic bushings 518 that are secured to the body 504. Asshown in FIGS. 36-37, each bushing 518 extends through the thickness ofthe body 504—that is, each bushing 518 extends through the pin guide'sbone-engaging surface 508 and outer surface 510. As shown in FIG. 37,each bushing 518 includes an elongated bore 520 that extendstherethrough. The bore 520 is sized to receive a drill such that thepatient's femur may be pre-drilled prior to installation of the guidepins 102. Each bore 518 is also sized to receive a corresponding guidepin 102, as shown in FIG. 37. It should be appreciated that in otherembodiments the pin guide 500 may be configured for use with removabledrill bushings similar to those described above in regard to the femoralpin guide 100.

The body 504 has a cutting guide slot 522 formed near its distal end524. The cutting guide slot 522 is an elongated slot extending in theanterior/posterior direction. The cutting guide slot 522 extends throughthe entire thickness of the body 504 and is thereby being open to boththe bone-engaging surface 508 and the outer surface 510. As can be seenin FIG. 36, a metallic cutting guide 502 is secured within the cuttingguide slot 522 of the body 504. The cutting guide 502 lines the cuttingguide slot 522 and is embodied as a captured cutting guide (i.e., it isclosed on all sides so as to capture a saw blade therein) including asubstantially planar cutting guide surface 526. The cutting guide 502 issized and shaped to receive the blade (not shown) of a surgical saw orother cutting instrument and orient the blade to resect the distalsurface of the patient's femur during an orthopaedic surgical procedure.In the illustrative embodiment, the cutting guide 502 is positioned suchthat the surgeon may begin the resection with the primary femoralprosthetic component still attached the patient's femur.

As shown in FIG. 36, the arm 506 of the pin guide 500 includes aprosthesis-facing or engaging surface 530 and an outer surface 532opposite the prosthesis-facing surface 530. The prosthesis-engagingsurface 530 includes a negative contour 534 that is configured toreceive a portion of the lateral condyle 416 of the primary femoralcomponent 14 having a corresponding contour. In the illustrativeembodiment, the negative contour 534 of pin guide 500 includes a curvedinner surface 536 that is shaped to match the curved condyle surface 34of the lateral condyle 416. As such, the negative contour 512 of thebone-engaging surface 508, in conjunction with the negative contour 534of the prosthesis-engaging surface 530, permits the pin guide 500 to bepositioned on the patient's femur 18 in a unique predetermined locationand orientation, as shown in FIG. 37.

Referring now to FIGS. 38-41, the customized patient-specificinstruments described herein may be embodied as a customizedpatient-specific tibial pin guide 600. The tibial pin guide 600 isconfigured to be coupled to the implanted primary tibial tray 22 andhence the patient's tibia 26. As described in greater detail below, thepin guide 600 is used to install a pair of guide pins 102 in a locationon the tibia 26 that has been preplanned and customized for thatparticular patient. In the illustrative embodiment, the pin guide 600 isconfigured such that the guide pins 102 are inserted into the lateralside of the proximal end 24 of the patient's tibia 26. It should beappreciated that in other embodiments the pin guide 600 may beconfigured to insert the pins 102 into the medial side or anterior sideof the patient's tibia 26. Like the femoral pin guide 100, the tibialpin guide 600 is devoid of a cutting guide; as such, other cuttingblocks are required to resect and shape the distal end 16 of thepatient's femur 18 to receive a revision tibial prosthetic component.

As shown in FIG. 38, the pin guide 600 includes a main body 612configured to engage the primary tibial tray 22 of the primary kneeprosthesis 12 and a support body 614 configured to be coupled to thelateral side of the patient's tibia 26. The pin guide 600 may be formedfrom a material such as a plastic or resin material. In someembodiments, the pin guide 600 may be formed from a photo-curable orlaser-curable resin. In one particular embodiment, the pin guide 600 isformed from a Vero resin using a rapid prototype fabrication process. Itshould be appreciated that in other embodiments the pin guide 600 may beformed from other materials in other embodiments. For example, inanother particular embodiment, the pin guide 600 is formed from apolyimide thermoplastic resin, such as an Ultem resin. In theillustrative embodiment described herein, the pin guide 600 is embodiedas a monolithic structure.

The main body 612 of the pin guide 600 includes a prosthesis-engagingsurface 620 and an outer surface 622 opposite the prosthesis-engagingsurface 620. As shown in FIG. 39, the prosthesis-engaging surface 620 ofthe main body 112 includes a negative contour 624 that is configured toreceive a portion of a platform 626 (see FIG. 38) of the primary tibialtray 22 having a corresponding contour. In the illustrative embodiment,the negative contour 624 of pin guide 600 includes a curved innersurface 628 that is shaped to match the convex curved surface 630 of theplatform 626.

The pin guide 600 also includes a shaft 632 that is sized to be receivedin a stem bore 634 formed in the tibial tray 22. As shown in FIG. 38,the shaft 632 extends away from the main body 612. The shaft 632 ispositioned such that the pin guide 600 is located in a unique positionand orientation relative to the tibial tray 22.

The support body 614 of the pin guide 100 includes a bone-contacting orbone-facing surface 640 and an outer surface 642 opposite thebone-facing surface 640. As shown in FIG. 40, the bone-facing surface640 includes a negative contour 644 configured to receive a portion ofthe patient's tibia 26 having a corresponding contour 646. In theillustrative embodiment, the negative contour 644 includes a uniqueplurality of depressions and ridges 648 that match a correspondingplurality of depressions and ridges of the corresponding contour 646 ofthe patient's tibia 26. The negative contour 644 of the bone-facingsurface 640, in conjunction with the negative contour 624 of theprosthesis-engaging surface 620 and the shaft 632, permits thepositioning of the pin guide 600 on the patient's tibia 26 in a uniquepredetermined location and orientation. In other embodiments, thenegative contour 644 of the bone-facing surface 640 may be omitted.

It should be appreciated that in other embodiments the customizedpatient-specific pin guide may be configured to engage other portions ofthe primary tibial prosthetic component. For example, the pin guidemight include a negative contour that is configured to receive a portionof the posterior edge of the primary tibial tray. In other embodiments,the pin guide might include a negative contour that is configured toengage the locking flange of the primary tibial tray.

The pin guide 600 also has a number of metallic bushings 650 secured tothe body 614. Each bushing 650 extends through the thickness of the body614—that is, each bushing 650 extends through the pin guide'sbone-engaging surface 640 and outer surface 542. As shown in FIG. 41,each bushing 650 includes an elongated bore 652 that extendstherethrough. The bore 652 is sized to receive a drill such that thepatient's tibia may be pre-drilled prior to installation of the guidepins 102. Each bore 652 is also sized to receive a corresponding guidepin 102, as shown in FIG. 41. It should be appreciated that in otherembodiments the tibial pin guide may be configured for use withremovable drill bushings similar to those described above in regard tothe femoral pin guide 100.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

1. A method of fabricating a customized patient-specific guide block,the method comprising: generating a image of a patient's bony anatomyand an implanted prosthetic component secured to the patient's bonyanatomy, identifying landmarks on the patient's bony anatomy and theprosthetic component, selecting a revision surgical instrument based theimage and the landmarks, and manufacturing the customizedpatient-specific guide block including a customized prosthesis-specificnegative contour shaped to match a corresponding contour of theimplanted prosthetic component, the customized prosthesis-specificnegative contour includes a concave surface shaped to match a convexsurface of the corresponding contour of the implanted prostheticcomponent.
 2. The method of claim 1, wherein selecting the revisionsurgical instrument includes generating a second image showing a plannedposition of the revision surgical instrument relative the patient's bonyanatomy.
 3. The method of claim 2, further comprising manufacturing asecond customized patient-specific guide block based on the plannedposition of the revision surgical instrument, the second customizedpatient-specific guide block including an indicator of the plannedposition.
 4. The method of claim 1, further comprising selecting arevision orthopaedic prosthesis based the image and the landmarks. 5.The method of claim 4, wherein selecting the revision orthopaedicprosthesis: selecting a first revision orthopaedic prosthesis from aplurality of revision orthopaedic prostheses, overlaying a digitaltemplate of the first revision orthopaedic prosthesis on the image tocreate a second image showing the first revision orthopaedic prosthesisimplanted in the patient's bone, and selecting a second revisionorthopaedic prosthesis from the plurality of revision orthopaedicprostheses based on the second image.